LONDON.- What do you get if you cross a Christmas tree with a bicycle? A "Tree-Cycle" - A sustainable Christmas tree made out of recycled bicycle parts.

Leading sustainable architectural practice Sarah Wigglesworth Architects has been commissioned by developer's igloo to create a bespoke Christmas tree for Bermondsey Square, London, SE1. The Bermondsey Square Christmas tree is composed of 35 recycled bike wheels, set on a simple structure, in the recogniZable shape of a Christmas Tree.

The 35 wheels incorporated in the design are on loan from UK charity Re~Cycle who are committed to providing cheap, sustainable transport in Africa. The charity collects redundant bicycle parts to restore bicycles, which are then shipped to Africa for use by local people and health workers coping with the AIDS epidemic.

Additional reflectors which act as fairy lights (without the need for energy) were kindly donated by local cycling shops Evans Cycles and On Your Bike, both on Tooley Street and Re~Cycle. The design has been manufactured as a kit of parts for future storage and reassembly. The structure breaks down into small elements, therefore it is easy to store on site and there is no need for transport. It will be reused every year.

Hatton Metalcraft fabricated and built the tree in one week and together with Sarah Wigglesworth Architects, Oblique Workshops and Structural Engineers Teckniker it was erected in the Square in a matter of hours.

The concept is for the wheels to be capable of moving under some form of renewable energy. Early versions of renewable energy involved people pedalling, connected to the wheels through bicycle chains, but wind power offered simplicity and speed, with each wheel acting like a tiny wind turbine attached to the end of every branch.

Sustainable design is a central tenant to sustainable investor igloo (an Aviva Investors Fund), the team behind the Bermondsey Square development. The buildings at Bermondsey Square are highly energy efficient with a communal energy plant. The mixed-use scheme benefits from a single energy centre with heat exchangers in each apartment and an adiabatic cooling system by which outside air is humidified and used to cool the circulating air. This form of natural ventilation delivers 60% reduction in carbon emissions and 50% lower running costs.

David Roberts, Deputy Chief Executive, igloo said: "The Bermondsey Square tree not only looks great; it can be used year after year.. It is designed so that it can be dismantled and stored. The bike wheels will be returned to Re~Cycle and will be used to recondition bikes for distribution to Africa. We also hope its presence in the Square will contribute to a number of measures we are taking to actively encourage cycling in London. A big thank you to the team involved who generously gave their time and to all those who donated parts."

Sarah Wigglesworth, Architect, said: "We were really excited when igloo asked us to design a sustainable Christmas tree. The team brainstormed a number of ideas during a design charette. A theme emerged, the idea of promoting green transport in the capital which relates to our cycle store, also in the Square. We are all proud of the resulting tree, and hope everyone enjoys it."